The invention relates to an implantable chamber for the infusion of a medicament, which chamber is to be implanted subcutaneously by way of an incision in a body.
Such chambers are already known; they comprise a medicament reservoir, a region for access to the reservoir, which region is accessible from outside the body and which is to enable the medicament reservoir to be filled, and a diffusion duct connected to the reservoir and extending outside the latter.
Such chambers may also be used in the opposite manner, that is to say, for taking a sample of body fluid (blood in particular), the fluid collecting in the chamber from which it can be removed. Such chambers also fall within the ambit of the invention but the invention will be described hereinafter purely with reference to a chamber for the infusion of a medicament without limiting the scope of the invention to infusion chambers only.
The chamber is to be implanted beneath the skin of a patient. In the course of such an operation, the surgeon makes an incision in the dermis, for example at the thorax, and inserts an implantable chamber entirely beneath the skin. During the operation, the end of an outlet duct from the chamber is accessible at the incision for the connection of a catheter which closes the infusion site, for example the jugular vein.
After implantation, a syringe, which is introduced via the access region, may be used as a source of medicament which has to be diffused progressively in the body, or for taking a sample.
Document U.S. Pat. No. 5,951,512 describes an implantable chamber which is to transfer a liquid transdermally between a reservoir and a diffusion region inside the body of a patient. It comprises a circular medicament reservoir, a support cheek surrounding the base of the reservoir, a region for access to the reservoir, which region is located towards the top of the reservoir, is accessible from outside the device and is to enable the medicament reservoir to be filled, and a diffusion duct which is connected to the reservoir and which extends radially or tangentially towards the outside of the latter.
Document DE-197 45 654 also describes an implantable chamber having a circular medicament reservoir and a support plate surrounding the reservoir, a diffusion duct connected to the reservoir extending radially towards the outside of the latter.
Documents U.S. Pat. No. 5,328,465, WO 02/083208, EP-678 302 and AT-391 813 describe medicament pumps and not implantable chambers. They all comprise a cylindrical or lenticular body having a circular cross-section, from which extends a diffusion duct which forms a bend such that the diffusion duct has a direction substantially tangent to the reservoir.
Accordingly, an implantable chamber for the infusion of a medicament is already known, which chamber is to be implanted subcutaneously by way of an incision in a body and which comprises a medicament reservoir, a region for access to the reservoir, which region is located at a vertex of the reservoir, is accessible from outside the body and is to enable the medicament reservoir to be filled, and a diffusion duct which is connected to the reservoir and which extends outside the latter, the diffusion duct having an external terminal portion.
Such a chamber poses the following problems. Since an incision has to be made in order to put it in place, the chamber is traumatising and it is desirable to reduce that traumatism as much as possible. The chamber constitutes a foreign body which causes some discomfort which depends in particular on its volume and its shape and also on how securely it is fastened beneath the skin. Finally, another important factor is the ease with which it can be put in place by the surgeon because the longer the intervention the greater the traumatism.